Coronary artery disease is the leading cause of death in the United States. Approximately 300,000 bypass grafts are performed annually. With this statistic in mind it is obvious that a more cost effective, less invasive system has to be developed. SonicStar has developed and patented an Ultrasonic Angioplasty system that is capable of dissolution of plaque and thrombus. We propose to examine an enhancement of this device by combining microwave antennas inside the catheter and examine the feasibility of a system for all disease ablation. The specific aims are (1) Development of a microwave antenna/catheter- to enhance or supplement the existing Ultrasonic device (2) Examine the feasibility of using the device in the treatment of arrhythmias and tachycardia. Preliminary simulations and experimental work have been encouraging. Focussed energy and selectivity are possible. particularly in the diseased vessel.